Rotary compressor

ABSTRACT

A rotary compressor includes a first compressing unit and a second compressing unit arranged one on top of another with a partition board therebetween. The partition board is provided with a vertical hole and a horizontal hole. After the front end of an injection copper tube to inject a refrigerant liquid is loose fit in the horizontal hole, an injection liner having an outer diameter larger than the inner diameter of the injection copper tube is inserted into the injection copper tube from the back end and is pressed up to the front end to increase the diameter of the front end of the injection copper tube such that the injection copper tube is tight fit in the horizontal hole.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2011-124892, filed on Jun. 3, 2011, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are directed to a rotary compressor.

BACKGROUND

A conventional hermetic rotary compressor comprises, in a closed container, a driver and a rotary compression element that is driven by the driver and includes two cylinders. For example, Japanese Laid-open Patent Publication No. H7-127575 discloses a conventional technology for cooling such a hermetic rotary compressor, in which a mounting metal piece fixed to an injection copper tube by pressure bonding or welding is positioned precisely to the center in the thickness direction of a partition board between the two cylinders. The inner diameter of a vertical through small hole for injection in the partition board is equal to the length to the upper and lower cylinders so that the same amount of refrigerant liquid is injected to the cylinders. The mounting metal piece fixed to the injection copper tube is attached to the partition board by screws.

In the conventional technology, if the mounting metal piece is fixed to the injection copper tube by pressure bonding, it cannot be fixed reliably because the injection copper tube is soft. If the mounting metal piece is fixed to the injection copper tube by welding, it cannot also be fixed reliably because the stress concentrates on a welding part due to the vibration of the rotary compressor. Further, the attachment of the mounting metal piece to the partition board with screws increases the cost by screwing.

SUMMARY

According to an aspect of an embodiment, a rotary compressor is configured to suck in refrigerant gas from the low pressure side of a refrigeration cycle, compress the refrigerant gas, and discharge the refrigerant gas to the high pressure side of the refrigeration cycle. The rotary compressor includes a compressor housing, a first compressing, a second compressing unit, and a partition board. The first compressing unit and the second compressing unit are located in the compressor housing, and are arranged one on top of another with the partition board between them. The partition board is provided with a vertical hole that is communicated with the first compressing unit and the second compressing unit, and a horizontal hole that is communicated with the vertical hole. An injection copper tube to inject a refrigerant liquid to the first compressing unit and the second compressing unit is loose fit in the horizontal hole. After the front end of the injection copper tube is loose fit in the horizontal hole, a columnar injection liner provided with an aperture and having an outer diameter larger than the inner diameter of the injection copper tube is inserted into the injection copper tube from the back end. The injection liner is pressed into the injection copper tube up to the front end to increase the diameter of the front end of the injection copper tube, which is loose fit in the horizontal hole, such that the injection copper tube is tight fit in the horizontal hole.

The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a vertical cross-sectional view of a rotary compressor according to an embodiment;

FIG. 2 is a horizontal cross-sectional view of first and second compressing units;

FIG. 3 is a partially enlarged vertical cross-sectional view of a compressing unit of the rotary compressor according to the embodiment; and

FIG. 4 is an enlarged view of a portion A in FIG. 3.

DESCRIPTION OF THE EMBODIMENT(S)

Exemplary embodiments will be described in detail with reference to the accompanying drawings.

FIG. 1 is a vertical cross-sectional view of a rotary compressor according to an embodiment. FIG. 2 is a horizontal cross-sectional view of first and second compressing units. FIG. 3 is a partially enlarged vertical cross-sectional view of a compressing unit of the rotary compressor according to the embodiment. FIG. 4 is an enlarged view of a portion A in FIG. 3.

As illustrated in FIG. 1, a rotary compressor 1 of the embodiment comprises a compressor housing 10, a compressing unit 12, and a motor 11. The compressor housing 10 is a vertically placed cylindrical sealed housing. The compressing unit 12 is located in the lower part of the compressor housing 10. The motor 11 is located in the upper part of the compressor housing 10 and drives the compressing unit 12 via a rotation shaft 15.

The motor 11 includes a starter 111 and a rotor 112. The starter 111 is shrink fit to the inner periphery of the compressor housing 10 to be fixed thereto. The rotor 112 is located in the center of the starter 111 and is shrink fit to the rotation shaft 15 to be fixed thereto. The rotation shaft 15 mechanically connects between the motor 11 and the compressing unit 12.

The compressing unit 12 comprises a first compressing unit 12S and a second compressing unit 12T. The second compressing unit 12T is located in parallel above the first compressing unit 12S. The first compressing unit 12S includes a first cylinder 121S having a first flared portion 122S. The second compressing unit 12T includes a second cylinder 121T having a second flared portion 122T. The first flared portion 122S is provided with a first inlet 135S, a first vane groove 128S, and a first back-pressure chamber 129S. The second flared portion 122T is provided with a second inlet 135T, a second vane groove 128T, and a second back-pressure chamber 129T.

As illustrated in FIGS. 1 and 2, the first cylinder 121S and the second cylinder 121T have a circular first cylinder inner wall 123S and a circular second cylinder inner wall 123T, respectively, which are formed concentric with the motor 11. Inside the first cylinder inner wall 123S and the second cylinder inner wall 123T, a first annular piston 125S and a second annular piston 125T are arranged, respectively, which have a smaller outer diameter than the inner diameter of the cylinders. Between the first cylinder inner wall 123S and the first annular piston 125S, a first operation chamber 130S (compression space) is formed. Similarly, between the second cylinder inner wall 123T and the second annular piston 125T, a second operation chamber 130T (compression space) is formed. The first operation chamber 130S and the second operation chamber 130T compress refrigerant gas sucked therein and discharge the compressed refrigerant gas.

In the first cylinder 121S, the first vane groove 128S is formed from the first cylinder inner wall 123S along the radial direction over the height of the first cylinder 121S. A flat plate-like first vane 127S is slideably fitted in the first vane groove 128S in an air-tight manner. In the second cylinder 121T, the second vane groove 128T is formed from the second cylinder inner wall 123T along the radial direction over the height of the second cylinder 121T. A flat plate-like second vane 127T is slideably fitted in the second vane groove 128T in an air-tight manner.

As illustrated in FIG. 2, at the bottom of the first vane groove 128S and the second vane groove 128T, a first spring hole 124S and a second spring hole 124T are formed to be communicated with the first vane groove 128S and the second vane groove 128T from the periphery of the first flared portion 122S and the second flared portion 122T, respectively. In the first spring hole 124S and the second spring hole 124T is inserted a vane spring (not illustrated) to press the back of the first vane 127S and the second vane 127T. Usually, by the resilient force of the vane spring, the first vane 127S protrudes from the first vane groove 128S into the first operation chamber 130S, and the second vane 127T protrudes from the second vane groove 128T into the second operation chamber 130T. Accordingly, the end of the first vane 127S and the second vane 127T comes in contact with the peripheral surface of the first annular piston 125S and the second annular piston 125T. Thus, the first vane 127S partitions the first operation chamber 130S (compression space) into a first inlet chamber 131S and a first compression chamber 133S. Similarly, the second vane 127T partitions the second operation chamber 130T (compression space) into a second inlet chamber 131T and a second compression chamber 133T.

Further, in the first cylinder 121S, the first back-pressure chamber 129S is formed to allow the bottom of the first vane groove 128S to be communicated with the inside of the compressor housing 10 through an opening R illustrated in FIG. 1 to introduce compressed refrigerant gas inside the compressor housing 10. Similarly, in the second cylinder 121T, the second back-pressure chamber 129T is formed to allow the bottom of the second vane groove 128T to be communicated with the inside of the compressor housing 10 through the opening R to introduce compressed refrigerant gas inside the compressor housing 10. The first back-pressure chamber 129S and the second back-pressure chamber 129T apply a back pressure to the first vane 127S and the second vane 127T, respectively, by the pressure of the compressed refrigerant gas.

The first flared portion 122S of the first cylinder 121S is provided with the first inlet 135S that allows the first inlet chamber 131S to be communicated with the outside so that refrigerant can be sucked into the first inlet chamber 131S from the outside. The second flared portion 122T of the second cylinder 121T is provided with the second inlet 135T that allows the second inlet chamber 131T to be communicated with the outside so that refrigerant can be sucked into the second inlet chamber 131T from the outside.

As illustrated in FIG. 1, a partition board 140 is located between the first cylinder 121S and the second cylinder 121T to partition between the first operation chamber 130S of the first cylinder 121S and the second operation chamber 130T of the second cylinder 121T. A lower end plate 160S is arranged at the lower end of the first cylinder 121S to close the first operation chamber 130S of the first cylinder 121S. Meanwhile, an upper end plate 160T is arranged at the upper end of the second cylinder 121T to close the second operation chamber 130T of the second cylinder 121T.

A lower bearing 161S is formed in the lower end plate 160S. The lower bearing 161S rotatably supports a lower-bearing support portion 151 of the rotation shaft 15. An upper bearing 161T is formed in the upper end plate 160T. The upper bearing 161T rotatably supports an upper-bearing support portion 153 of the rotation shaft 15.

The rotation shaft 15 is provided with a first eccentric portion 152S and a second eccentric portion 152T, the phases of which are shifted by 180° to be eccentric. The first eccentric portion 152S is rotatably fitted to the first annular piston 125S of the first compressing unit 12S. The second eccentric portion 152T is rotatably fitted to the second annular piston 125T of the second compressing unit 12T.

When the rotation shaft 15 rotates, the first annular piston 125S rotates and revolves counterclockwise in FIG. 2 along the first cylinder inner wall 123S in the first cylinder 121S. Similarly, when the rotation shaft 15 rotates, the second annular piston 125T rotates and revolves counterclockwise in FIG. 2 along the second cylinder inner wall 123T in the second cylinder 121T. Along with the movement of the first annular piston 125S and the second annular piston 125T, the first vane 127S and the second vane 127T move back and forth. By the movement of the first annular piston 125S, the second annular piston 125T, the first vane 127S, and the second vane 127T, the volume of the first inlet chamber 131S, the second inlet chamber 131T, the first compression chamber 133S, and the second compression chamber 133T continuously changes. As a result, the compressing unit 12 continuously sucks in refrigerant gas and compresses it, thereby discharging the compressed refrigerant gas.

As illustrated in FIG. 1, a lower muffler cover 170S is located below the lower end plate 160S such that a lower muffler chamber 180S is formed between the lower end plate 160S and the lower muffler cover 170S. The first compressing unit 12S is open to the lower muffler chamber 180S. That is, near the first vane 127S of the lower end plate 160S, there is provided a first outlet 190S (see FIG. 2) that allows the first compression chamber 133S of the first cylinder 121S to be communicated with the lower muffler chamber 180S. The first outlet 190S is provided with a first outlet valve 200S that prevents the backflow of compressed refrigerant gas.

The lower muffler chamber 180S is a circular chamber and is part of a communication path that allows the outlet side of the first compressing unit 12S to be communicated with the inside of an upper muffler chamber 180T via a refrigerant path 136 (see FIG. 2) passing through the lower end plate 160S, the first cylinder 121S, the partition board 140, the second cylinder 121T, and the upper end plate 160T. The lower muffler chamber 180S reduces the pressure pulsation of discharged refrigerant gas. A first outlet valve cap 201S and the first outlet valve 200S are fixed one on top of the other by a rivet to control the warping opening amount of the first outlet valve 200S.

As illustrated in FIG. 1, an upper muffler cover 170T is located above the upper end plate 160T such that the upper muffler chamber 180T is formed between the upper end plate 160T and the upper muffler cover 170T. Near the second vane 127T of the upper end plate 160T, there is provided a second outlet 190T (see FIG. 2) that allows the second compression chamber 133T of the second cylinder 121T to be communicated with the upper muffler chamber 180T. The second outlet 190T is provided with a second outlet valve 200T that prevents the backflow of compressed refrigerant gas.

A second outlet valve cap 201T and the second outlet valve 200T are fixed one on top of the other by a rivet to control the warping opening amount of the second outlet valve 200T. The upper muffler chamber 180T reduces the pressure pulsation of discharged refrigerant gas.

The first cylinder 121S, the lower end plate 160S, the lower muffler cover 170S, the second cylinder 121T, the upper end plate 160T, the upper muffler cover 170T, and the partition board 140 are integrally fastened by a bolt 175. Among the compressing unit 12 integrally fastened by the bolt 175, the outer periphery of the upper end plate 160T is fixed to the compressor housing 10 by spot welding, and thereby the compressing unit 12 is fixed to the compressor housing 10.

In the outer peripheral wall of the cylindrical compressor housing 10, a first through hole 101 and a second through hole 102 are formed in this order from the bottom to be separated from each other in the axial direction to let a first inlet tube 104 and a second inlet tube 105 pass therethrough. Besides, on the outside of the compressor housing 10, an accumulator 25 formed of an independent cylindrical sealed container is held by an accumulator holder 252 and an accumulator band 253.

The top center of the accumulator 25 is connected to a system connecting pipe 255 that is connected to the low pressure side of the refrigeration cycle. The accumulator 25 is provided with a bottom through hole 257 at the bottom. The bottom through hole 257 is connected to a first low-pressure communication tube 31S and a second low-pressure communication tube 31T. One end of the first low-pressure communication tube 31S and the second low-pressure communication tube 31T extends to the upside in the accumulator 25, and the other end is connected to an end of the first inlet tube 104 and the second inlet tube 105.

The first low-pressure communication tube 31S and the second low-pressure communication tube 31T guide the low-pressure refrigerant of the refrigeration cycle to the first compressing unit 12S and the second compressing unit 12T, respectively, via the accumulator 25. The first low-pressure communication tube 31S is connected to the first inlet 135S (see FIG. 2) of the first cylinder 121S via the first inlet tube 104 as an inlet. The second low-pressure communication tube 31T is connected to the second inlet 135T (see FIG. 2) of the second cylinder 121T via the second inlet tube 105 as an inlet. That is, the first inlet 135S and the second inlet 135T are communicated in parallel with the low pressure side of the refrigeration cycle.

The top of the compressor housing 10 is connected to an outlet tube 107 that is connected to the high pressure side of the refrigeration cycle to discharge high-pressure refrigerant gas to the high pressure side of the refrigeration cycle. That is, the first outlet 190S and the second outlet 190T are communicated with the high pressure side of the refrigeration cycle.

Lubricant oil is enclosed in the compressor housing 10 up to about the height of the second cylinder 121T. The lubricant oil circulates in the compressing unit 12 by a vane pump (not illustrated) inserted beneath the rotation shaft 15. Thus, the lubricant oil seals a portion that partitions the compression space of compressed refrigerant with the lubrication of sliding parts and tiny gaps.

With reference to FIGS. 3 and 4, a description will be given of a salient structure of the rotary compressor 1 according to the embodiment. As illustrated in FIG. 3, the partition board 140 is provided with a vertical hole 141 and a horizontal hole 143. The vertical hole 141 is communicated with the first operation chamber 130S of the first compressing unit 12S and the second operation chamber 130T of the second compressing unit 12T. The horizontal hole 143 is communicated with the vertical hole 141 via a horizontal communication hole 142. An front end portion 144 a of an injection copper tube 144 for liquid injection is loose fit in the horizontal hole 143. The inner diameter of the horizontal communication hole 142 is smaller than that of the horizontal hole 143, and is larger than the inner diameter (for example, 1.0φ) of an aperture 145 a of an injection liner 145, which will be described later. The vertical hole 141, which is located separate from the horizontal hole 143, is communicated with the horizontal hole 143 through the horizontal communication hole 142 having a small inner diameter. Accordingly, the machine work is easier compared to the case where the horizontal hole 143 having a large inner diameter is directly communicated with the vertical hole 141. Further, at the assembly of the injection copper tube 144 and the injection liner 145, the front end portion 144 a of the injection copper tube 144 and an end portion of the injection liner 145 come in contact with an end surface of the horizontal hole 143 and thus are positioned, resulting in effective assembly.

The front end portion 144 a of the injection copper tube 144 passing through the compressor housing 10 is loose fit in the horizontal hole 143. After that, the columnar injection liner 145 provided with the aperture 145 a and having an outer diameter larger than the inner diameter of the injection copper tube 144 is inserted into the injection copper tube 144 from a back end portion 144 b and is pressed up to the front end portion 144 a. This increases the diameter of the front end portion 144 a of the injection copper tube 144, which is loose fit in the horizontal hole 143, to be tight fit in the horizontal hole 143. At the assembly of the refrigeration cycle, an injection communication tube 146 is connected to the back end portion 144 b of the injection copper tube 144.

As illustrated in FIG. 4, it is assumed, for example, that the injection copper tube 144 has an outer diameter a of 6.35φ, an inner diameter b of 4.75φ, and a thickness c of 0.8 mm. In this case, if the inner diameter d of the horizontal hole 143 is 6.5φ(a gap 0.15 mm), and the outer diameter e of the injection liner 145 is larger than the inner diameter b of the injection copper tube 144 by about 0.2φ, i.e., 4.95φ, the front end portion 144 a of the injection copper tube 144 is pressure bonded to the horizontal hole 143 (interference 0.05 mm) and can be firmly fixed in an air-tight manner.

From the aspect of workability and rigidity, the injection liner 145 is preferably made of an iron-based material (for example, carbon steel S45C, S50C, etc.). The aperture 145 a (for example, having an inner diameter of 1.0φ) of the injection liner 145 prevents an excessive increase in injection amount to the first operation chamber 130S of the first compressing unit 12S and the second operation chamber 130T of the second compressing unit 12T. Besides, the aperture 145 a can serve as a capillary tube as a narrow tube that prevents the backflow of compressed refrigerant.

As described above, according to the embodiment, the injection copper tube 144 can be reliably fixed to the partition board 140. Moreover, since screw fixing and a capillary tube are not used, the rotary compressor can be obtained at a low cost.

All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment(s) of the present inventions have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. 

1. A rotary compressor configured to suck in refrigerant gas from a low pressure side of a refrigeration cycle, compress the refrigerant gas, and discharge the refrigerant gas to a high pressure side of the refrigeration cycle, the rotary compressor comprising: a compressor housing; a first compressing unit in the compressor housing; a second compressing unit in the compressor housing, the first compressing unit and the second compressing unit being arranged one on top of another; and a partition board between the first compressing unit and the second compressing unit, wherein the partition board is provided with a vertical hole that is communicated with the first compressing unit and the second compressing unit, and a horizontal hole that is communicated with the vertical hole, an injection copper tube to inject a refrigerant liquid to the first compressing unit and the second compressing unit is loose fit in the horizontal hole, and after a front end of the injection copper tube is loose fit in the horizontal hole, a columnar injection liner provided with an aperture and having an outer diameter larger than an inner diameter of the injection copper tube is inserted into the injection copper tube from a back end and is pressed up to the front end to increase a diameter of the front end of the injection copper tube, which is loose fit in the horizontal hole, such that the injection copper tube is tight fit in the horizontal hole.
 2. The rotary compressor according to claim 1, wherein the horizontal hole is communicated with the vertical hole via a horizontal communication hole narrower than the horizontal hole.
 3. The rotary compressor according to claim 1, wherein the injection liner is made of an iron-based material. 